Gas Powered Gun Barrel

ABSTRACT

An improved barrel system for gas powered guns that improves the performance of the guns, by employing adjustable inserts in slots in the barrel to provide an effective barrel diameter less than the bore diameter. The barrel system may optionally include barrel liners, inserts and spin-control components.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit and priority from U.S. Provisional Patent Application 61/667,521, filed Jul. 3, 2012, the contents and disclosure of which are incorporated herein by reference for all purposes.

BACKGROUND

1. Field of the Invention

This invention relates to improved barrel systems and barrels for gas powered guns such as paintball guns and airsoft guns. More specifically, it relates to a gas powered gun barrel system with adjustable inserts to provide an effective barrel diameter that improves the performance of the guns.

2. Background

Obtaining a correct match of barrel diameter with projectile (paintball) diameter is a significant problem with paintball (marking) gun performance. Because paintballs have pliable skin and a soft (usually liquid) center, the diameter is not consistently uniform and varies with temperature and other ambient conditions. Moreover, paintball projectiles from the same manufacturer vary in diameter slightly from batch to batch, which leads to unpredictable shot placement and poor accuracy. Different manufacturers also specifically make paintballs in different diameters. If the barrel diameter is too small it produces excess drag and stress on the ball which can seriously impede its velocity and can cause the projectile to rupture in the barrel. A barrel with an inner diameter too large will cause a paintball to ricochet in the barrel as it travels along the barrel and exit in an unpredictable path resulting in unstable trajectory and inconsistent accuracy. Traditional barrels, when sized correctly create two (2) stress points on the paintball projectile. Those points are on the equator of the ball. Most balls are created from two (2) halves mated together where the ends overlap, creating the slightly larger equator of the ball. This method of paintball manufacturing is very similar to the manufacturing of medicine capsules. More than two contact points would be desirable.

Others have tried to address the problem of barrel and ball match with grooved or “rifled” barrels-see U.S. Pat. No. 6,453,593 and U.S. Pat. No. 7,802,393. But these patents disclose grooved barrels that are of fixed diameter and do not adequately address the problems of variation in ball diameter nor are they adjustable. U.S. Pat. No. 6,823,857 describes a popular method of changing effective barrel diameter by providing varying diameter replacement barrels.

The barrel system of this invention, having variable inserts, allows for three or more points of contact and is easily adjustable or tunable to optimize the effective barrel diameter. The more contact points there are on the paintball, the more distributed the force is on the paintball. This enables players to shoot more brittle paintballs that are more likely to break on their target. Using more brittle paintballs in traditional barrels makes them more likely to break in the barrel.

The barrel/insert system of the present invention allows for different designs of inserts to be used in the same barrel. The inserts are tailored to achieve the effect and action desired. In one embodiment, flexible or elastomeric inserts flex to allow for a dynamic inner diameter effect.

When ball breaks do occur in the barrel, traditional barrels force the paintball to pass through the broken paintball shell pieces which can alter the paintball path unpredictably and result in poor accuracy. The system of this invention allows balls to shoot through a broken ball more easily since the ball never touches the barrel bore surface; it reduces contact with the broken paintball shell pieces.

SUMMARY

A gas powered gun barrel system comprising a barrel having slots, inserts to fit into the slots and, optionally, means, such as a cover, to hold the inserts into position when in use. In broad aspect the system comprises a barrel (hollow cylinder) either as a single section or multiple sections having a plurality of longitudinal slots, each less than the length of the barrel.

In one embodiment there is also provided means at the distal end of the barrel for effecting spin on a traversing ball.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of a slotted barrel of an embodiment of the invention.

FIG. 1B is an isometric view of a barrel insert of an embodiment of the invention.

FIG. 1C is isometric views of a liner for a breech adapter of an embodiment of the invention.

FIG. 1D is isometric views of another liner for a breech adapter of an embodiment of the invention.

FIG. 2 is an isometric view of another slotted barrel of an embodiment of the invention.

FIG. 3A is an isometric view of a barrel insert of an embodiment of the invention.

FIG. 3B is a side view of a barrel insert of an embodiment of the invention.

FIG. 4 is a series of figures, 4A-4I, of end view cross sections of barrel inserts.

FIG. 5 is an isometric view of a barrel with snap-in adaptable slots.

FIG. 6 is an end view of a barrel with inserts in place.

FIG. 7 is an isometric view of a barrel with cover attached.

FIG. 8 is an isometric view of a barrel with sections showing a section of the barrel with an inner liner and a section of an inner liner of one embodiment of the invention.

FIG. 8A is an end view of a barrel with sections showing a section of the barrel with an inner liner and a section an inner liner of one embodiment of the invention.

FIG. 8B is an end view of a barrel with sections showing a section of the barrel with an inner liner and a section an inner liner of one embodiment of the invention.

FIG. 9 is an isometric view of a two piece barrel of one embodiment of the invention.

FIG. 10 is an isometric view of a three piece barrel of one embodiment of the invention.

FIG. 11A is an isometric view of a spin adapter for use in one embodiment of the invention.

FIG. 11B is an isometric inside view of a spin adapter for use in one embodiment of the invention.

FIG. 11C is also an isometric inside view of a spin adapter for use in one embodiment of the invention.

FIG. 12 is an isometric view of a barrel of one embodiment of the invention showing a spin adjustment means on the distal end of the barrel.

FIG. 13A is also an isometric inside view of another spin adapter for use in one embodiment of the invention.

FIG. 13B is also an isometric inside view of another spin adapter for use in one embodiment of the invention.

FIG. 13C is also an isometric inside view of another spin adapter for use in one embodiment of the invention.

DETAILED DESCRIPTION

The gas powered gun (such as a paint gun or marking gun) barrel system of the invention comprises a barrel having slots, inserts to fit into the slots and, optionally, means, such as a cover, to hold the inserts into position when in use. The system of the present invention is also useful for Airsoft guns that can shoot small caliber, 0.50 caliber paintballs which can benefit from the system of this invention in the same way as paintball guns, e.g. centering the ball, putting spin on the ball etc.

In broad aspect the system comprises a barrel (hollow cylinder) having a plurality of longitudinal slots for receiving inserts, each less than the length of the barrel, wherein the slots are arranged in sets.

Preferably, in a single barrel embodiment, there are at least two sets of slots spaced around the circumference of the cylindrical barrel at the breech or proximal end of the barrel, one set offset from the other and spaced longitudinally on the barrel. The slots may or may not overlap longitudinally. In a preferred embodiment they do not overlap, but inserts fit into the slots with a portion that extends beyond the slot opening inside the barrel to accomplish much the same effect as overlapping slots. In an embodiment in which the slots do overlap, each set partially overlaps a slot longitudinally in the next adjoining set and is spaced apart from the slots of the other set so the paintball does not experience a loss of contact with inserts over the length of the barrel. In this embodiment the projectile material support structure is not compromised by sharp or irregular ends of slots that may cut into the projectile. It is preferred that the slots not span the length of the barrel so as to allow variation in types and placement of the inserts. In a two piece (or multi-piece) barrel described below there is at least one set of slots in the breech end barrel section and one set in the distal end barrel section.

The barrel slots (openings through the barrel wall) provide housing for inserts. It is beneficial to have three (3) inserts (three rows of slots) so that there are three contact points on the projectile ball instead of the normal two as is the case with a smooth bore barrel where the larger circumference of the ball (where the halves of the ball are joined in manufacture) contacts the barrel inside wall. The more contact points that touch the ball, the less force is exerted per contact point which, in turn allows the use of more brittle paintballs. The added contact points reduce the chance of the paintball breaking in the barrel and increase the chance of the paintball breaking on target. U.S. D559,923 is a design patent of a barrel having slots but the slots are not of the kind disclosed in this invention—the slots not being opened through the barrel wall except at the distal end.

The system of the invention allows for different effects on the paintball to be obtained by varying the kind of insert used and by the placement of the inserts in the barrel. The inserts provide the ability to change the effective inner diameter of the barrel. The inserts help to ensure centering of the paintball projectile when there is a poor bore size to paintball match; in one embodiment by using inserts that flex to change the effective inner diameter dynamically. In some embodiments the inserts are designed to induce spin on a paintball by using inserts that provide a large surface area for friction on one side of the paintball, while using inserts with a low surface area and low friction on the opposite side of the paintball. The system can be arranged to create a choke effect with different sized inserts creating larger effective inner diameters on one end of the barrel then transitioning to smaller effective inner diameters on the other end of the barrel. Traditional barrels place great importance on honing the finish of the inner diameter of the barrel, to make it as smooth as possible in order to lower the drag that, in turn, causes the paintball to spin and lead to unpredictable flight paths and inaccuracy. Over time this finish degrades. Dropping the barrel can also scuff up the inner end of the barrel, all leading to increased chances of breaking paintballs in the barrel. In the system of this invention barrel bore finish is not an issue since the ball does not contact the bore wall but only the insert surface. Inserts are easily changed, a solution far less expensive than a purchasing a new barrel.

The system is very adaptable since the barrel can be made from different materials, the position of slots can be varied, the size and shape of slots can be different, the total number of slots can be changed and the orientation of the slots can be varied. Inserts can have diverse design shapes that create special effects on the path of the paintballs and can made of different materials. Attachment of the inserts in the slots is also very adaptable as they may be held in place by a cover, clamps, magnetically, physically attached to the barrel or secured by a snap fit design as detailed below.

The optional use of an inner barrel liner (or barrel sections of different diameters) will enable more efficient use of gas propellants by limiting the amount of void space around the paintball. As used herein and in the claims the term “slots” mean longitudinal, generally rectangular, openings extending entirely through the wall of the barrel, the opening having a length to width ratio of at least 2/1, and preferably 4/1.

Barrel

Referring to the Figures, FIGS. 1A, 1B and 2 are perspective (isometric) views of an embodiment of a barrel, 100, and insert 290 of this invention. The barrel has a proximal or breech end, (where lead line 182 points in FIGS. 1 and 101 points in FIG. 2), and distal or exit end, (where 185 lead line points in FIGS. 1 and 102 points in FIG. 2). The proximal end (182 and 155) is the end of the barrel that connects to the paintball gun (“marker”) breech and the distal end is the end where projectiles exit the barrel. The breech end is shown in FIG. 1 with a breech end adapter 182-183 and in FIG. 2 with a threaded section, 155. The breech end will be made to be fitted on the breech of the gun to which it is to be attached. The threaded end 155 enables the barrel to be connected to the female threads of the breech of a paintball gun (or Airsoft gun). Most modern paintball guns have barrels that screw into a front receiver on the gun. Older types slide the barrel on and screw it in place. Barrel threading will be matched to that of the gun to be used. Common threads are: Angel, Autococker, Impulse/Ion, Shocker, Spyder, A-5, and 98 Custom.

Alternatively, adapters are provided (182/183 of FIG. 1) that attach to the barrel by any suitable means, including pressure fit, threaded, quick disconnect fitting, means to attach different threaded breech adapters to the barrel or attach multiple barrels together, means to attach a muzzle to the distal end of the barrel or any other means that will be apparent to those skilled in the art. The use of adapters is useful since only the adapters will need to be customized for different gun connections. Breech adapters may have liners, 184 and 186, as shown in FIGS. 1C and 1D. The liners as shown have a lips 185 and 187, to help hold them in place. The liner such as shown in FIG. 1C is useful to reduce the bore diameter of the adapter and thus allow less gas to escape forward, thereby increasing the efficiency. The adapter shown in FIG. 1D, 186, is designed to provide ridges for the projectile ball to ride upon serving the same purpose of the inserts in the barrel. The liner has ridges that fit into slots in the adapted body 185. This adds to the efficiency in the same manner as the liner of FIG. 1C but adds protection for the paintball projectile by preventing contact with the full inside bore of the liner. Both liners are shown with threads 188, to allow attachment to female threads in the breech of a gun. Connectors other than threads may also be used.

In some embodiments the distal or exit end may have a support ring at the end; see 140 in FIGS. 12 and 162 in FIG. 9. It is preferred that the ring, if used, be knurled (patterned) to provide a good grip for threading the barrel into the gun and aids in threading the barrel into the threaded breech of the gun.

The barrel is shown in FIG. 1 with seven sets of slots (openings through the wall of the barrel), each set with three slots. FIG. 5 shows seven sets of slots. The slots are preferably arranged equidistance around the circumference of the barrel (120° on center for three slots). Inserts can be snap-fitted into the slots as is explained in the section following and can be constructed with a longer length inside the barrel than the length of slot opening to provide an overlap of the inserts and provide smooth transition of the projectile as it travels from one set of inserts to the next. In one embodiment (FIG. 2) each set of slots is arranged so that the overlap is longitudinal (proximal end of each slot of the second set of slots begins before the distal end of the slots of the first set ends.) Each set overlaps the other (though spaced apart around the circumference e.g. 60° from the adjacent slot in the preceding set.) The overlap typically will be at least two (2) percent of the length of the slot and may be up to about twenty (20) percent. An overlap of about five to ten (5-10) percent is very suitable. These same overlap dimensions are also suitable for overlap of inserts that fit into slots that do not overlap.

Longitudinal overlap of the slots or of the inserts provides smooth transition of the ball as it travels from one set of slots or inserts to the next. The overlap allows for a continuous effective barrel diameter inside the barrel as explained below. Spacing other than equidistance around the circumference may be appropriate for some circumstances, but in general, equidistance spacing is preferred. As shown in FIGS. 1 and 2 the slots have tapered sides, 110, and ends. This embodiment allows inserts with matching tapered sides to be placed into the slots but leaves the outside surface of the insert even with or slightly above that of the outside surface of the barrel. This allows the inserts to be more securely held in place by a cover or by other means. It is suitable but not preferred to have the surface of the insert at or below the surface of the outside of the barrel so as to leave a smooth surface of the outside diameter of the barrel—as can be seen in FIG. 6. Tapered as the term is used herein and in the claims means the sides of the slots are sloped from top (outside wall of the barrel) to bottom (inside surface of barrel bore). Tapered slot openings will, therefore be larger at the outside barrel surface than at the inside barrel bore surface. This allows inserts that are tapered to mate with the tapered slots to be placed in the slots without passing through the slots. Many variations in slot configuration are possible, those of FIGS. 1A and 2 being illustrative of preferred embodiments. In most preferred embodiments except in a multi-piece barrel, a set of the slots will be placed near (within about ten (10) percent of the length of the barrel from the end) the proximal (breech) end of the barrel—if multiple slot sets are used they may extend the length or a substantial portion of the barrel. In a multi-piece barrel described following, the slots may be placed at the breech end and the slots in separate pieces of the barrel of the multi-piece barrel may extend to the end of the piece and converge with another like slot of an adjoining piece. Moreover, the slots on the breech adapter end may be inverted from normal and be tapered so that the larger side of the taper is on the outside circumference. This prevents the inserts from dislodging as the paintball moves past them. This configuration is useful when the barrel is inside a breech adapter or the barrel cover is too thick to fit inside the marker breech and cannot hold those inserts in place.

The placement of slots allows inserts to be placed where the balls will have maximum air pressure, a feature that distinguishes the slots of this invention from previous barrel designs with openings for venting usually placed near the distal end of the barrel. It is, of course, within the scope of the invention to have slots only on the distal end but this would reduce many of the advantages of the invention and is not preferred.

The inserts are preferably held in place in the slots by a snap-fit design as shown in FIGS. 1 and 1A. As shown in FIG. 1A the slots 110 have a rounded end 184. This allowed the insert shown in FIG. 1B to be inserted. The insert (290) illustrated in FIG. 1B has a projection 294 at one end and a snap connector 292 at the other end. The front is configured to slide into the rounded part of slot 184 and extend beyond the slot opening. The other snap end is configured so that when pushed down into the slot, the part 292 flexes upward to allow the insert to seat. When seated, 292 flexes downward to its original position to secure the insert into the slot. The extension 294 of the insert that fits into 184 allows the insert to overlap adjacent inserts arranged around the barrel circumference without the necessity of overlapping the slots.

In another embodiment, grooves, of which 120 is one, shown in FIG. 2 are optionally provided to accommodate O rings that hold the inserts in place until a cover or other means to hold them in place is applied. Paintball diameter and therefore gun barrel nominal inside or bore diameter, generally range from 0.50 to 0.695 caliber (inches), and barrels are made to match these diameters. A nominal diameter of about 0.68 caliber (inch) is typical and common. Typical barrels are between 3 inches (76 mm) and 21 inches (530 mm) long, with custom barrels up to about 36 inches (910 mm) long. FIG. 2 also illustrates the threaded breech end of the barrel and an optional banded exit end, 140.

Rather than the inserts slot patterns as those shown in FIG. 4A-4I, insert-like ridges may be formed or permanently attached into the barrel inter surface or in a barrel liner (described below). While this embodiment lacks flexibility to change and mix and match inserts it eliminates the need for a cover or other means to hold the inserts in place. The ridging can, for example, be accomplished by over-molding in an injection molding process to permanently attach inserts. Ridged sections can also be attached inside the barrel or liner by adhesive or other suitable attachment means. In another embodiment an elastomeric coating is applied that would perform the same function as the inserts. The ridges may suitably be rigid or be flexible (malleable).

Barrel Inner Liner

There is also optionally provided an inner barrel liner to be used in the barrel to reduce the annular space formed between the barrel actual bore diameter and the effective diameter formed by the inserts. Generally these will be of shorter length than the barrel and disposed at the breech or proximal end of the barrel. Liners are further explained in the Insert section—see FIG. 8. This inner liner will have slots matching the barrel slots for the inserts to be placed in the barrel wall. Generally, the inner liner will not extend far beyond half the length of the barrel (or less) or be more than about eight (8) inches in length. The liner may also be tapered, having a smaller diameter (greater wall thickness) at the breech end. U.S. Pat. No. 7,775,200, Oct. 17, 2010 discloses a tapered composite liner for barrels but not a liner that has slots as in the present invention.

Multi-Piece Barrel

In another embodiment, illustrated in FIGS. 9 and 10, there is provided a multiple piece (or multi-section) barrel, 150 and 160 (preferably two or three piece). This allows a selection of barrel sections, like 150, that may be of various diameters to accomplish results similar to those obtained by the barrel liner described above. Rather than providing liners of different diameter, there are barrel sections of different diameter. Different bore diameter barrel section will accommodate different projectile sizes and conditions and provide less annular space between the projectile and inside barrel surface. This is the same effect as achieved with the liners illustrated in FIGS. 8A and 8B. The breech section will have a configuration such as that illustrated in FIG. 8A (except the barrel bore will be a single piece and not have the liner 132). The distal end view will be much like that illustrated in FIG. 8B. Thus, the annular space between the barrel bore and the effective diameter will be smaller in the breech end section than in the distal section. In general, the breech sections, 150, will have a smaller diameter than the bore diameter of section 160. The forward or distal section will generally be of a fixed bore diameter and not need to be changed. The breech section and distal sections will be connected together, 166 and 156, by suitable means such as threaded connection, pressure fit, quick connect fitting or any other means that will be apparent to those skilled in the art. Items 168 and 158 are the slots in the barrel like 110 in FIG. 2. Item 162 is an end piece. The raised ring as shown in FIGS. 9 and 10 are useful to prevent a cover from sliding over the distal end. This requires the cover to be attached from the proximal end. The distal end shown in FIGS. 1 and 5 have a female groove to allow a cover with an internal ring to snap fit onto the barrel. This requires the cover to attach from the distal end.

As shown in FIG. 9 the breech section may be connected to the breech of the gun by means such as item 155 or by an optional third section, 170, shown in FIG. 10 or 182 and 183 in FIG. 1. The breech adapter, 170, will have means for attaching to the breech of the gun with varying connector ends to accommodate the different attachment means, generally female threads at the point that 170 points (threads not shown) for attaching the gun breech as described above. Part 172 mates with part 152 to connect the adapter, 170, to the barrel section 150, by any suitable means, generally by male threads on 152 and female threads on 172. The end of the breech section may be sloped to provide smooth transition to the somewhat larger bore diameter of the distal section. The breech section may also have a tapered internal bore diameter generally with the smaller diameter at the breech end. The bore diameters will be of nominal 0.68 caliber, for example, diameters of 0.687, 0.689, 0.693 and 0.697 inches.

Another embodiment is a breech adapter with the ability to house barrel liners of different diameters.

The barrel may be made of any suitable material, including, but not limited to, steel, stainless steel, aluminum, copper, brass, shape memory alloys and/or polymers, and other more exotic metals and synthetic materials such as engineered polymer materials, plastics, reinforced polymers such as fiberglass, carbon fiber reinforced polymers and the like.

Spin Control Embodiment

In another embodiment the barrel system is fitted with means to impart top, side or backspin on the paintball. U.S. Pat. No. 7,699,048 describes a paintball barrel attachment that imparts backspin on the ball as it exits the barrel attachment by providing an adjustable means to provide friction on the top of the ball which causes it to begin to rotate backwards. In the '048 patent this is accomplished by an inverted trough that tilts slightly from the direct line of flight of the ball. The tilt, downward incline, of the trough may be adjusted by a slideable wedge mechanism that pushes the trough downward to increase the incline. In one embodiment of the present invention, friction is exerted on the ball to cause backspin (or other spin direction) by an insert in a slot in the barrel and adjusted by the extent the insert extends into the barrel bore. Referring to FIGS. 11A, 11B and 11C and 12, 400 is a clamp the fits over a set of insert openings at the distal end of the barrel, 232, 234 and 236 (FIG. 12). 402 is a handle attached to a slide mechanism placed in slot 401. 402 is attached to a wedge piece 406 (FIG. 11B). When slid forward 402 and 406 push downward on strip (projection) 404. 404 is a strip the fits into groove 112 (FIG. 12) and is attached at the end sections so that the strip may be pushed downward. This strip in groove 112 pushes down on an insert such as insert 200 in FIG. 3A that fits into slots 232, 234 and 236. When the wedge mechanism, represented by 402 and 406, is moved forward 404 forces the associated insert further into the barrel opening. When the insert extends further into the barrel bore than other forward inserts (those toward the breech end) it exerts friction on the ball that will cause the ball to spin in a manner similar to the mechanism of U.S. Pat. No. 7,699,048. Any insert around the circumference may be activated by rotating the clamp 400 to a suitable position over the desired insert(s). It is preferred for spin control that there be four insert openings (and inserts) arranged around the circumference of the barrel spaced 90° apart rather than the normal three. Four equally spaced inserts will allow the choice of a spin producing insert at the top, bottom or either side. While the illustrated embodiment shows clamp 400 only on the terminal set of inserts, a second clamp may be used for the penultimate set or a single clamp may be fashioned to cover more than one set of inserts. It is preferred that only the end set be used.

In another embodiment the spin adapter is shown in FIGS. 13A, 13B and 13C. This adapter is a separate cylindrical piece that attaches to the end of the barrel rather than build into the distal end of the barrel as is the case of the spin adapter shown in FIGS. 11 and 12. The insert(s) (not shown) may be fully seated in the slots of the 428 housing and cannot be adjusted to extend into those slots more/less or they may be seated with a void space between the insert and backstop so that the projectile pushes the insert into the void space. Adjustment is made by the position of the backstop. The 426 backstop sits above the 428 insert housing. This 426 backstop is what the insert(s) hit when the paintball passes, pushing the insert(s) upwards into the 426 backstop. This 426 backstop can be adjusted closer or farther from the insert(s) by switch or slide 424. The closer the 426 backstop to the insert(s), the more aggressive the spin since the insert(s) provide a slight, controlled obstruction to the paintball path. The farther the 426 backstop to the insert(s) the less aggressive the spin since the insert(s) provide less obstruction of the paintball's path. Instead of adjusting the 426 backstop from the top only, as shown in the Figures, there can also be a rotating adjustment. This embodiment can be a cap that can be twisted to adjust or a means similar to that of U.S. Pat. No. 7,603,998, the relevant disclosure of which is incorporated herein by reference. Additionally, the slideable mechanism is only one means of adjustably forcing an insert into the barrel bore opening and other means will be apparent to those skilled in the art. Any inserts will be suitable but flexible or elastomeric inserts described herein will generally be preferred.

Inserts

FIGS. 3A and 3B are isometric perspective views that illustrate embodiments of the inserts of the invention. The insert shown in FIG. 3A has a curved top, 201, that matches the outside curve of the barrel, tapered sides, 202, which mate with tapered sides of the slots illustrated in FIGS. 1 and 2, and a flat bottom 205. Other cross sections and insert configurations are shown in FIG. 4, 4A-4I. FIGS. 4A-4C illustrate inserts with tapered sides (252, 255 and 258) to fit into mated tapered edges (110) of slots. Any of the cross sections 4A-4I can have tapered sides as well. FIGS. 4D-4I illustrate inserts having tops that project above the surface of the outside of the barrel (260, 264, 266, 272, 276 and 281). It is preferred that the surface 261, 265, 269, 273, 277 and 282 be curved to match the curve of the outside diameter, but extend slightly above the surface of the barrel. In one embodiment the inserts will have a flexible or malleable bottom section to allow dynamic (change with force of projectile) sizing of the effective diameter. If the insert section in contact with the ball is elastic, it will adjust for slight differences in the ball diameter. In general, the entire insert will not be elastic or flexible but only the bottom section that fits inside the barrel—see 211, 212 and 213 in FIG. 6. These elastic inserts may be constructed by any suitable means that will be apparent to those skilled in the art. An example is to construct the body of the insert of moldable elastomeric polyurethane. This will allow manufacturing flexibility as different shapes and different hardness can be easily adjusted in a molded product. The outward body of the insert will, for example, be relatively hard (Shore A hardness of 80 or more) but the bottom section that fits inside the barrel (⅓ to ⅛ of bottom) will be soft—Shore A of 30 or less.

The bottom of the inserts, that is the surface that is placed inside the barrel and forms the sides of the effective diameter barrel bore, may be any as shown in FIGS. 4A-4I or any other suitable configuration that will be apparent to those skilled in the art. The fairly wide flat bottom, 253 and 274, are easy to machine and provide a large surface for the ball to ride upon. In a properly sized effective diameter, the balls should ride upon the same small center of the insert, no matter the insert width. The shape will depend upon the desired results. For the least surface contact with the paintball a convex or sharp bottom (259, 266, 271) may be optimal. To obtain the most surface area to increase friction as to induce a spin on the paintball, concave underside may be optimal (363). Inserts of difference thickness (distance extending into the barrel) may easily be placed in any slot in the same barrel if the inserts all have the same footprint (shape) to fit into the slot. FIG. 4H shows a dual or slotted surface 280 and 279 which may be desirable to increase contact points but not surface drag. FIG. 4I illustrates a design that is curved across the width of the bottom of the insert where the part 284 curves across the bottom from one end to the opposite side 285 at the other end of the insert. This provides a rifling effect to add spin to the ball. A shape that is designed to score the outer shell of the paintball projectile will cause the projectile to break more easily upon contact with a target.

These cross sections are merely illustrative and are not inclusive of all possible configurations. The important dimension of the inserts is that they be sized to extend into the barrel, that is, extend beyond the inside surface of the inside bore diameter of the barrel. This will provide an effective diameter (diameter of a circle that would touch the inserts) smaller than the inside bore diameter of the barrel. The bottom (underside, usually shaped) of the insert are the only points of contact for the paintball projectile—paintballs do not touch the inner bore surface of the barrel. Different types of inserts can be used to provide different benefits, but can all fit the same barrel. For example, the thickness (distance from top to bottom) of the inserts determines the effective inner diameter of the barrel. This provides a means to obtain a better match of the barrel to the size of paintballs. Inserts may also be sectioned, shaped to fit together to make a single insert and may be connected together in any conventional way such as by an interlocking configuration. Sectioned inserts will be useful where the slot is relatively long as when one slot substantially traverses the length of the barrel. The insets may also be ported to allow venting of pressure at the distal section of the barrel.

Since the effective diameter is less than the actual inside bore diameter of the barrel there is an annular space between the ball and the inside bore surface which is an added benefit. The annular space allows gas to surround the ball as it traverses the barrel, to escape and thus reduce noise and also provide a space for the debris of balls broken in the barrel. Traditional barrels use porting (holes in the barrel) to lessen the noise signature of the barrel by lowering the air pressure behind the ball to atmospheric pressure once the paintball passes the first ported holes.

The present invention allows for annular areas between the barrel inner diameter and the paintball for air pressure to equalize and lessen the “pop” when the paintball exits the barrel. Generally, porting in traditional barrels is located near the distal or exit end of the barrel since it would be undesirable to port the barrel near the breech end and exhaust the air pressure at that point. In the present invention the barrel may also include traditional porting.

When ball breaks do occur, traditional barrels force the paintball to pass through the broken paintball shell pieces and can alter the paintball path unpredictably resulting in poor accuracy. The annular space of the barrel with inserts allows the ball to shoot through the break more easily since the ball never touches the bore surface of the barrel and the debris will be located in the annular space. It does not have to pass through the broken paintball pieces and paint.

In one aspect there is also provided an inner barrel insert or liner to be used in the breech or proximate longitudinal section of the barrel as shown in FIG. 8. This liner will allow greater gas pressure at the breech end of the barrel by reducing the annular area but allow an expanded annular space in the distal or exit end of the barrel. This will allow more gas to escape at the distal end around the ball and reduce noise and better position the ball. In general this inner insert will be less than about half the length the barrel and no more about ¾ the barrel length. Inner tubes of four (4) to eight (8) inches will usually be suitable no matter the length the barrel. For most barrels 8-10 inches is usually the effective barrel length which is the distance over which the ball is accelerating. However, the inner liner may be shorter. This inner liner will have slots matching the barrel for inserts to pass through the barrel and liner walls. As with the barrel bore surface it is not intended that the balls touch the inner liner surface. The inserts may also be mixed and matched. In one arrangement the insert set or sets near the distal (exit) end of the barrel may be thicker (extend farther into the bore) to provide a smaller effective diameter to obtain a choking effect—use of narrower inserts (for a higher inner diameter effect) on the proximal end of the barrel with thicker inserts (for a lower inner diameter effect) on the distal or exit end of the barrel.

FIG. 5 shows a barrel having seven sets of slots with three slots in a set. There may be as few as two sets of at least two slots and preferably three slots or as many as can be placed on a barrel. In a multi-piece barrel the breech adapter may have only one bank of slots but, in general, in most configurations, there will be at least two. The number of inserts should, in general, be at least three arranged around the circumference of the barrel and can be as many as seven or nine, in odd or even numbers. In the two-piece barrel there will be at least one set for each section of barrel. More than nine would be cumbersome but not outside the scope of the invention. FIG. 5 illustrates slots that have tapered sides for placement of tapered inserts so that the surface of the barrel with inserts in place is smooth or with the inserts projecting slightly above the outer barrel surface. This makes a neat appearance and facilitates the use of a cover (as discussed below) but is not essential to the function of the invention. FIG. 6 is an end view of a barrel having at least two sets of three inserts in each set. The barrel 100 has an inside surface 105. The inserts in one set, 211, 212 and 213 are spaced equidistance around the circumference of the barrel. The next set of inserts 221, 222 and 223 are further along the length of the barrel and offset from the first set. The dimension aD in FIG. 6 is the effective diameter between the surface of the inserts and bD is the bore diameter. The difference is the annular space, a, between the effective diameter (aD) of the barrel and the barrel bore.

The inserts as shown have a transition taper (203 on FIGS. 3A and 3B) on the back (breech or proximal end) to transition from the inner diameter of the barrel to the inner diameter of the insert. This prevents the ball from being clipped or punctured when moving from one set of inserts to the next.

Inserts may be made of many different materials, including but not limited to, steel, stainless steel, aluminum, copper, brass, other more exotic metals such as shape memory alloys, magnetic metals and synthetic materials such as engineered polymer materials, elastomers, plastics, reinforced polymers such as fiberglass, carbon fiber reinforced polymers and the like. The inserts may be different colors or in a variety of colors or may be engraved with numbers or symbols to aid in identification. This is especially useful where there is a variety of inserts to be used for different projectiles or shooting situations. Color coding the inserts will allow easy identification.

Cover

A cover is used in some embodiments to hold inserts in place. Before the cover is in place, the inserts have to be in proper position. The cover keeps all inserts pushed against the barrel and prevents the inserts from moving outwards when the projectiles contact them. For this purpose, in one embodiment, there are optional grooves, 120, for O rings in the barrel and in each insert, 220. The O rings are installed first held in position by the grooves, to keep the inserts from falling out before the cover is installed over the O rings and insert.

The O rings are not essential as the user can simply hold inserts in place manually or use other methods to hold them in position until they are secured as by a cover. The cover may also have apertures positioned so that inserts may be adjusted through with the cover in place. The cover also gives the barrel a neat appearance and provides added support.

Other means such as clamps, pressure fitted inserts, hook and loop (Velcro™) straps, tape or other like means may be used to hold inserts to the barrel instead the cover.

An embodiment with the cover in place is shown in FIG. 7. The cover also provides additional structural support for the barrel. The aesthetics of the cover may also be enhanced by anodizing and/or machine designed cuts. If the barrel is ported the cover may be ported as well.

The cover may be a single piece as shown, in multiple pieces that snap together or otherwise connected, or may be in the form of multiple clamps to accomplish the same purpose. Clamps can clamp onto the barrel where the O ring slots are shown in FIGS. 2, 3A and 3B. There would be a need to purchase only one (1) clamp per bank of inserts. The cover may be constructed of any suitable material, metal, polymer, elastomeric polymers and the like, it being only necessary that it have sufficient structural strength for holding the inserts in place. Additionally, the cover and/or barrel may be made from a translucent/transparent material with the means to add lighting effects (from a LED light for example) to the barrel system. These effects can have different modes (constant on, strobe, etc.) and can be triggered by sound of the projectile being shot, movement of the marker. The cover may be made from an elastomeric material that will flex slightly as the paintballs contact the internal inserts. This allows the inserts to momentarily become unseated as it is pushed by the paintball. In another aspect, there is provided a muzzle piece that can be attached to the end of the cover to provide different aesthetics. This type of aesthetic is generally preferred by the military simulation sector of Paintball enthusiasts. See, for example, the discussion at the web site http://www.wolfpackpaintballteam.com/paintball/paintball-muzzle-brakes.html

While the invention has been particularly shown and described as referenced to the embodiments thereof, those skilled in the art will understand that the foregoing and other changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims. The specification is, accordingly, to be regarded in an illustrative rather than a restrictive sense. The scope of the invention should be limited only by the appended claims. 

1. A barrel system for gas powered guns comprising a hollow cylindrical barrel having a plurality of longitudinal slots spaced around the circumference of the cylindrical barrel and inserts, portions of which that fit into the slots and extend through the barrel wall and beyond the surface of the inside wall of the barrel.
 2. The system of claim 1 wherein the inserts are constructed to snap fit into slots constructed to accommodate snap-fit inserts.
 3. The system of claim 1 wherein the inserts have a bottom cross section selected from the group consisting of flat, concave, convex, pointed, dual and curved.
 4. The system of claim 1 wherein the inserts are, at least partially, constructed of a flexible material.
 5. The system of claim 1 wherein there are at least two sets of slots spaced around the circumference of the cylindrical barrel, one offset from the other and spaced longitudinally on the barrel so that each slot in each set partially longitudinally overlaps a slot in the next adjoining set and is spaced apart from the slots of a second set; or the slots are spaced without overlap but with inserts configured to have a portion of the insert extend beyond the barrel surface inside the barrel so that inserts longitudinally overlap.
 6. The system of claim 1 wherein the slot opening and the inserts are structured to allow the insert to be fitted into the slot opening so that the inserts fit into the slots and the top surface of the insert(s) is positioned even with or extends slightly above the surface of the outside circumference of the barrel.
 7. The system of claim 1 wherein the barrel as a single piece or combined sections of barrel has a proximal end and a distal end and wherein the proximal end has an adapter that is adapted to mate with and connect to the breech connection of a gas powered gun.
 8. The system of claim 1 also comprising a means for holding the inserts in place when the system is in use.
 9. The system of claim 8 wherein the means is a cover.
 10. The system of claim 1 wherein the barrel comprises at least two sections, a proximal end section and a distal end section, that can be connected together to form a single slotted barrel.
 11. The system of claim 1 also comprising a slotted inner liner to be placed inside the bore of the barrel, wherein slots in the liner match and communicate with the slots in the barrel.
 12. The system of claim 7 wherein there is a removable liner that fits inside the adapter inside bore.
 13. The system of claim 12 wherein the 1 adapter is slotted and the liner grooved so that when assembled there are ridges inside the barrel for a projectile to ride upon.
 14. The system of claim 1 comprising means for inducing spin on a projectile located on or attached to the distal end of the barrel.
 15. The system of claim 14 wherein the distal end section has a cover and slideable wedge that engages a strip disposed on top of an insert that can flex downward to move an insert further into the bore of the barrel thereby exerting increased friction on a projectile in flight to cause it to spin.
 16. The system of claim 14 comprising housing for inserts located inside a cylindrical spin attachment attached to the distal end of the barrel and means to position the inserts into a portion of the bore of the barrel to contact a projectile passing through the attachment.
 17. A barrel system for gas powered guns comprising a hollow cylindrical barrel having narrow, shaped ridges disposed on the inside of the barrel or on the inside of a barrel liner, spaced around the circumference of the cylindrical barrel or liner.
 18. The barrel system of 17 wherein the ridges are malleable. 